Abstract
Purpose :
To examine the duty cycle of 23-Gauge (Ga) dual-pneumatic 10,000 cuts per minute (cpm) vitrectomy probes as a function of cut rate and various duty cycle modes then compare duty cycles of two dual-pneumatic probe designs at maximum cut rate: Group 1) 10,000 cuts per minute (cpm) vitrectomy probes and Group 2) previous generation, 7,500 cpm vitrectomy probes.
Methods :
Advanced UltraVit® and UltraVit® 23Ga vitrectomy probes were evaluated at cut rates of 500, 2,500, 5,000, 7,500, and 10,000cpm and at all three duty cycle modes (ie, Core, 50/50, and Shave) on the CONSTELLATION® Vision System. A Keyence digital high speed camera was focused on the port of the vitrectomy probe using a high magnification camera lens. The camera captured and recorded video of the probe tip during stabilized operation and video files were analyzed frame by frame to calculate the duty cycle. Shutter speed and frame rate were recorded. Duty cycle was measured as the percent of open cycle time (OCT) to whole cycle time (WCT). The OCT was the duration with which the cutter was more than halfway open. The WCT was the duration of 1 cut cycle. Average duty cycle and standard deviations were reported. A Welch’s statistical T-Test was used to compare the duty cycle of both groups at maximum cut rate.
Results :
Core duty cycle ranged from 56.95-82.22% as cut rate increased from 500 to 10,000cpm while Shave duty cycle ranged from 20.27-56.47% with increasing cut rate. In the 50% mode, duty cycle ranged 51.51-56.76%. When comparing 10,000cpm probes to previous generation 7,500 cpm probes at maximum cut rate, there was a 9-12% increase in the Core, 50%, and Shave duty cycle modes (+4.87%, p<0.05; +5.72%, p<0.05; +5.95%, p<0.05).
Conclusions :
The 23Ga dual-pneumatic probes operating at a maximum cut rate of 10,000cpm generated significantly higher duty cycles than previous generation probes operating at 7,500cpm. The performance of 23Ga vitrectomy probes appears to be optimized at 10,000cpm.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.